no, never saw a bare-knuckle prizefight-- where would you watch such a thing? the key here is 'prizefighter.' hang out in a bar long enough and you'll see your share of barfights, and these are really ordinary people. crack someone's ribs with a good one, and he'll spit up some blood. i've had to watch my buddy do that, and it sucked. it hurt him enough to kick back for the rest of the melee. and i saw a guy flat-out clock him square in the face that dropped him like a rock. he got up, but he was dazed. had the guy not seen me coming, my buddy would have been toast.
i'll grant that if you do 500 sit-ups a day and someone gives you a stomach blow, you can take it. the average person? hm. seeing as how the average person doesn't go to the gym that often, i question that. you take one to the solar plexus, and your vision is muddy, that i know from personal experience. and if you bang around a guy's head, you might break his nose, and the 'average' person is effectively done after that. break my nose, fight's done. don't get me wrong, i know a few people who you could beat with a crowbar and it not phaze them one lick-- these are not regular guys, though, adrenaline or not.
when you box, you have to take into consideration the fact that there are different ounce gloves that, indeed, cause varying impacts. that's one major reason why sugar ray leonard beat hagler, because leonard worked it into the contract they had to fight using the weight he wanted. wearing a mouthpiece is crucial to lessening the damage, too. without mouthpieces, these guys wouldn't have lips after awhile, lol. having had the opportunity to hang out with aaron 'the hawk' pryor several times, i tell ya the end result of 'prizefighters' ain't pretty. nice guy from what you can understand of what he's saying. another thing is, these guys have to have their hands registered as lethal weapons.
you're right, it hurts like hell to punch someone's head sometimes. i still have a scar on my hand where i knocked a guy's tooth out, and i'm glad that's where the fight stopped. here a couple of years ago i thought i'd broken a knuckle on a guy's windshield, and it took about a week for the swelling and pain to go away. hitting a guy in the forehead is gonna hurt, especially if he's not rolling with the punches. and if a boxer's hand is wrapped wrong, he'll break his hand on his first punch. boxers also fight in a stylized way, so it's really a poor example of how a realistic, extended fight would proceed in real life, where someone might pick up a board or pipe and smack the other guy in the thigh if he had to. it's not more believable than the hero getting shot in the upper chest and laughing it off. 'hell, yeah, it hurts, but i'm still having sex with you tonight, baby.' anyway, my understanding of one of the first things they teach you when you go into a boxing gym is you shouldn't be there if you want to learn self defense.
my point is, pull an aveage guy off the street and put him through the same punishment, say, indiana jones took while fighting the german mechanic (around the nazi airplane in the first movie), and it's going to be a quick fight. normal people in real life don't rebound nearly as fast as they do in the movies. kind of like when you kick someone in the crotch, they just shake it off and five seconds later are running around like nothing ever happened. uhm, not true, lol. even prizefighters wearing protection are given, what, five minutes for a low blow to recouperate?
i'd always heard the best way to knock someone out is with an uppercut. it 'cuts' the same way as JR described, i think, but your chances are better with an actual knock-out blow as opposed to a side-hit. that's why, too, when you hit someone square in the face, it more often than not stuns them for a moment... and brings on major reconstructive surgery (seen that one, not pretty). an uppercut to the nose can kill someone, though.